This invention relates generally to an adjustable strike for receiving a latch bolt of a swinging door, and more particularly concerns a strike having a movable wall which can bear against the camming surface of the latch bolt of the door to secure the door in position against a door stop.
The latch bolt of a door normally has a beveled cam surface and a flat keeper surface, the latch bolt being spring-projected from the door but, upon exertion of a superior force, depressable into the door panel. The superior force is provided by a lip or cam, usually inclined or curved, which cams the latch bolt inwardly as the latch bolt rides over it while the door is closing. When the door is closed, the latch bolt is properly aligned opposite the opening of the strike, and the bolt springs outwardly into this opening and a cavity behind it. Door movement is limited in one direction by the stop which forms part of the door jamb and, in the other direction, by the keeper surface of the latch bolt bearing against an edge of the opening of the strike.
In hanging a swinging door having a latch bolt, great care and skill must be exercised in ensuring that the hole of the strike plate secured to the door frame, and the latch bolt projecting from the swinging edge of the door are properly aligned so that the door will be securely held against the door stop. This alignment is critical not only in the vertical direction so that the lactch bolt will fit between the upper and lower edges of the opening in the strike, but also in the lateral direction so that the door, when in closed position, with its latch bolt fully extended into the cavity of the strike, cannot vibrate and rattle between the door stop and the strike. Consequently, in hanging a door, a carpenter will often first install the strike and then, through a slow, cumbersome, difficult process of alignment, next locate the latch bolt of the door in the strike plate and then determine where the hinges of the door should be located.
Alternatively, when the door is hinged first, it is not always possible to prepare the hole beneath the strike and fasten the strike in position on the door frame with the desired degree of accuracy. Often the location of the strike must be readjusted. While this may only be a slight amount, this usually means resetting the screws.
Other times, although the door may originally be hung in proper position, through settling of the building or warping of the door or frame, the strike may become misaligned with respect to the latch bolt so that, again, the strike or the door must be adjusted accordingly.
Moreover, in climates experiencing harsh winter conditions, doorways are often insulated before each winter by securing a band of insulation material or "weatherstripping" along the doorstep particularly where the swinging edge of the door meets the doorstop. This extra strip of insulation material between the door and doorstop may be sufficient to prevent the latch bolt from reaching the hole of the strike when the door is closed, so that the strike must be re-positioned.
An adjustable strike has been described in U.S. Pat. No. 3,161,429 of Torno, et al., issued Dec. 15, 1964, in which the lip and a marginal portion of the pocket of the strike are movable towards or away from the door or door jamb to reduce the clearance between the door and latch bolt and these portions of the strike. Canadian Pat. No. 721,030 of Russell, issued Nov. 9, 1965 describes and illustrates an adjustable strike in which the tongue and a marginal portion of this pocket are adjustable in the other, lateral direction by loosening two screws set in the face of the strike for this purpose, sliding the adjustable part to the proper position, and then retightening the screws. Both strike mechanisms require the assembling of several different parts, when installing the strikes.
Other references describing and illustrating strike mechanisms adjustable in the lateral direction are Canadian Pat. No. 674,967 of Schlage, issued Nov. 26, 1963, which describes a single strike plate having a tongue or flange extending into the pocket or cavity behind the plate, the tongue being bendable to provide a secure fit for the latch bolt, and Canadian Pat. No. 863,789 of Schlage, et. al., issued Feb. 16, 1971, which describes and illustrates a circular strike having a laterally adjustable cam or lip which is secured in place by a screw. The screws of this particular mechanism, as well as the screws securing the adjustable portions of the Torno, et al. mechanism and the Russell, et al. mechanism previously referred to, are all clearly visible on the face of the plate and are operated from that direction.
The adjustable strike of Schlage, Canadian Pat. No. 863,789 and one described and illustrated in Model, Canadian Pat. No. 319,005 issued Jan. 19, 1932, have shoulders which are adjustable within the cavity behind the strike to restrict the play of the latch bolt in the strike opening. However neither of these mechanisms provides more than a shoulder or edge against which the keeper surface of the latch bolt can react when a door is closed, thus constituting an inherent weakness in each device. Also, the mechanism described and illustrated in the Model patent requires a set of tracks to guide the shoulder as it slides across the plate hole. The shoulder is adjusted by means of a bolt threaded through a flange of that shoulder, the bolt having a screw head rotatably secured in a rivet. These features add significantly to the complexity of the device and to the costs of manufacturing it.
Other references of background interest are Lundbert, Canadian Pat. No. 295,934, issued Dec. 24, 1929 and Schlage, U.S. Pat. No. 2,869,913, issued Jan. 20, 1959, both of which describe and illustrate strike mechanisms having adjustable features.
It is an object of the present invention to provide an economical, readily constructed and readily installed adjustable strike for the bolt of a swinging door which will permit easy lateral adjustment of the edge of the strike against which the keeper surface of the latch bolt bears when the door is closed, to a position which ensures a secure fit of the latch bolt and minimizes vibration or play of the closed door. It is a further object of the invention to provide an adjustable strike having secure engagement of the latch bolt in the pocket thereof. It is a further object of the invention to provide such an adjustable strike in which the adjustment mechanism is well hidden so as to provide a neat attractive appearance.